A noun is a word that names a person, a place, a thing, or an idea.
When a noun names an actual person, we call it a proper noun. A proper noun must be capitalized.
Your name is a proper noun. All people’s names are proper nouns:
Sam
Betty
Mrs. Smith
Mr. Rogers
A noun can name an actual place. The names of special places are proper nouns:
Washington, D.C.
Orlando, Florida
London, England
Anchorage, Alaska
The names of special buildings are also proper nouns:
United States Capitol
the White House
National Gallery of Art
Lincoln Memorial
Schools are special buildings, so school names are always proper nouns.
Lincoln Elementary School
Harvard University
Maine South High School
North Central College
Proper nouns name actual people or places. A proper noun must always be capitalized.